docs/library/machine.I2C: Deconditionalise all methods.
The cc3200 port is now similar enough to the standard machine.I2C API so that all conditionals can be removed.
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Damien George
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c49b265389
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1f1a03d0c3
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@ -9,86 +9,55 @@ level it consists of 2 wires: SCL and SDA, the clock and data lines respectively
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I2C objects are created attached to a specific bus. They can be initialised
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when created, or initialised later on.
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.. only:: port_wipy
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Printing the I2C object gives you information about its configuration.
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Example::
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Example usage::
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from machine import I2C
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from machine import I2C
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i2c = I2C(0) # create on bus 0
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i2c = I2C(0, I2C.MASTER) # create and init as a master
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i2c.init(I2C.MASTER, baudrate=20000) # init as a master
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i2c.deinit() # turn off the peripheral
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i2c = I2C(freq=400000) # create I2C peripheral at frequency of 400kHz
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# depending on the port, extra parameters may be required
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# to select the peripheral and/or pins to use
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Printing the i2c object gives you information about its configuration.
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i2c.scan() # scan for slaves, returning a list of 7-bit addresses
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.. only:: port_wipy
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i2c.writeto(42, b'123') # write 3 bytes to slave with 7-bit address 42
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i2c.readfrom(42, 4) # read 4 bytes from slave with 7-bit address 42
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A master must specify the recipient's address::
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i2c.init(I2C.MASTER)
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i2c.writeto(0x42, '123') # send 3 bytes to slave with address 0x42
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i2c.writeto(addr=0x42, b'456') # keyword for address
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Master also has other methods::
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i2c.scan() # scan for slaves on the bus, returning
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# a list of valid addresses
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i2c.readfrom_mem(0x42, 2, 3) # read 3 bytes from memory of slave 0x42,
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# starting at address 2 in the slave
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i2c.writeto_mem(0x42, 2, 'abc') # write 'abc' (3 bytes) to memory of slave 0x42
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# starting at address 2 in the slave, timeout after 1 second
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i2c.readfrom_mem(42, 8, 3) # read 3 bytes from memory of slave 42,
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# starting at memory-address 8 in the slave
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i2c.writeto_mem(42, 2, b'\x10') # write 1 byte to memory of slave 42
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# starting at address 2 in the slave
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Constructors
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------------
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.. only:: port_wipy
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.. class:: I2C(id=-1, \*, scl, sda, freq=400000)
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.. class:: I2C(bus, ...)
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Construct and return a new I2C object using the following parameters:
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Construct an I2C object on the given bus. `bus` can only be 0.
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If the bus is not given, the default one will be selected (0).
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.. only:: not port_wipy
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.. class:: I2C(id=-1, \*, scl, sda, freq=400000)
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Construct and return a new I2C object using the following parameters:
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- `id` identifies the particular I2C peripheral. The default
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value of -1 selects a software implementation of I2C which can
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work (in most cases) with arbitrary pins for SCL and SDA.
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If `id` is -1 then `scl` and `sda` must be specified. Other
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allowed values for `id` depend on the particular port/board,
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and specifying `scl` and `sda` may or may not be required or
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allowed in this case.
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- `scl` should be a pin object specifying the pin to use for SCL.
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- `sda` should be a pin object specifying the pin to use for SDA.
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- `freq` should be an integer which sets the maximum frequency
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for SCL.
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- `id` identifies the particular I2C peripheral. The default
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value of -1 selects a software implementation of I2C which can
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work (in most cases) with arbitrary pins for SCL and SDA.
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If `id` is -1 then `scl` and `sda` must be specified. Other
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allowed values for `id` depend on the particular port/board,
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and specifying `scl` and `sda` may or may not be required or
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allowed in this case.
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- `scl` should be a pin object specifying the pin to use for SCL.
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- `sda` should be a pin object specifying the pin to use for SDA.
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- `freq` should be an integer which sets the maximum frequency
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for SCL.
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General Methods
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---------------
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.. only:: port_wipy
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.. method:: I2C.init(scl, sda, \*, freq=400000)
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.. method:: I2C.init(mode, \*, baudrate=100000, pins=(SDA, SCL))
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Initialise the I2C bus with the given arguments:
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Initialise the I2C bus with the given parameters:
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- ``mode`` must be ``I2C.MASTER``
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- ``baudrate`` is the SCL clock rate
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- ``pins`` is an optional tuple with the pins to assign to the I2C bus.
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.. only:: port_esp8266
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.. method:: I2C.init(scl, sda, \*, freq=400000)
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Initialise the I2C bus with the given arguments:
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- `scl` is a pin object for the SCL line
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- `sda` is a pin object for the SDA line
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- `freq` is the SCL clock rate
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- `scl` is a pin object for the SCL line
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- `sda` is a pin object for the SDA line
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- `freq` is the SCL clock rate
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.. method:: I2C.deinit()
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@ -102,8 +71,6 @@ General Methods
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those that respond. A device responds if it pulls the SDA line low after
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its address (including a write bit) is sent on the bus.
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Note: on WiPy the I2C object must be in master mode for this method to be valid.
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Primitive I2C operations
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------------------------
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@ -204,12 +171,3 @@ methods are convenience functions to communicate with such devices.
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On WiPy the return value is the number of bytes written. Otherwise the
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return value is `None`.
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Constants
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---------
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.. data:: I2C.MASTER
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for initialising the bus to master mode
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Availability: WiPy.
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